Ultrasonic Sensor Icing Detection via Phase Transition Analysis
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Solution Overview
Problem
Existing methods for detecting the icy and dirty states of ultrasonic sensors in motor vehicles are not reliable due to ambient temperature dependencies and cannot accurately determine the degree of icing or contamination.
Innovation Solution
A method that involves exciting the ultrasonic sensor membrane for a predetermined time interval, analyzing the phase change in the electrical sensor signal during the transition from excitation to independent oscillation, and comparing it with stored reference values to determine the icy or dirty state, allowing for reliable detection independent of ambient temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the decay time of the membrane is used to detect the icy/dirty state, then the detection method is simple, but the reliability is reduced because decay time depends on ambient temperature
Solution Approach 1:
The patent changes the detection parameter from decay time to phase change during the transition to independent oscillation. This phase change parameter is less sensitive to ambient temperature variations, thereby improving detection reliability while maintaining operational simplicity.
Solution Approach 2:
The patent replaces the temporal measurement (decay time) with a phase-based measurement during the transition to independent oscillation. This substitution allows differentiation between temperature effects and actual sensor blockage, improving reliability without complicating the detection process.
2Loss of information
If the decay frequency of the membrane is used to detect the icy/dirty state, then the detection method provides frequency-based information, but the measurement precision is reduced because it cannot distinguish temperature effects from icing effects
Solution Approach 1:
The patent changes the measurement parameter from decay frequency to phase change during the transition to independent oscillation. This phase parameter provides more precise information about the sensor's mechanical state, enabling accurate distinction between temperature variations and actual blockage conditions.
3Reliability
If the ultrasonic sensor membrane is excited for a long excitation time interval, then the independent oscillation signal is stronger, but the detection time is increased
Solution Approach 1:
The patent utilizes the membrane's natural independent oscillation that occurs automatically after excitation stops. By analyzing the phase change during this self-oscillation transition, the system obtains strong diagnostic signals without requiring prolonged excitation, thus reducing detection time while maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise determination of the icy or dirty state and the degree of contamination, with the ability to emit a warning signal to inform the driver, ensuring accurate distance measurements and sensor functionality.
Implementation Method 1
An electrical sensor signal, which characterizes the mechanical vibration of the membrane, is generated by means of a transducer element—for example a piezo element
Data Source
Figure 1~2
Figure 3~6
AI summary
The method involves energizing a diaphragm (3) of an ultrasonic sensor (2) to a mechanical vibration for a predetermined excitation time interval (8) using a control device (5). The mechanical vibration of the diaphragm is converted to electrical sensor signal (7) using a transducer element (4), and is output to the control device. An alternation in phase of the electrical sensor signal is determined with a transition (10) of the predetermined excitation time interval for detecting icy or contaminated state of ultrasound sensor. Independent claims are included for the following: (1) a sensor device; and (2) a motor car.